The special guest of Water Loss Detectives workshop 2017  is Mr David Pearson. To know him better we addressed him a few questions:

Hello David! I am glad that you agreed to come to Romania and to share some of your experiences with us. We have some questions for you in order to know you better and those who will participate in workshop:

1. A few words about you :

Hello. Firstly it was a great pleasure to be asked and I was happy to accept. I was born in Yorkshire in England. Yorkshire is about 300km due north of London – in what is a beautiful part of the country although it was quite industrial in the area where I was born – lots of mills in those days associated with the textile industry. I attended the local grammar school and then went to Imperial College, London, for my degree in civil engineering. I specialised in
water and hydrology. I then worked for Binnie and Partners, an engineering consultancy, in London after graduating. I worked for both Twort and Law while at Binnie’s – joint authors of that great book – “Water Supply” by Twort, Lowther and Law. I then moved employees a couple of times and in 1975 ended up in the North West of England to working for North West Water Authority. I moved house to Cheshire where I still live. I continued to work with North West Water for 27 years seeing it through privatisation and then the name change to United Utilities. I left in 2002 and have had my own company for 15 years now.

2. What do you do now? How long have you work in the field of water losses? Could you tell us something about your professional experience? How did you get in touch with this subject? Who taught you this?

I really enjoyed hydrology at university and manoeuvred myself into doing hydrology at Binnie and Partners. It was on my third job there that I met Allan Lambert (yes the one and only) for the first time – that was back in 1970! He worked for a client for a proposed reservoir development. Binnie’s had been employed to do the hydrological and physical design. I did the hydrological
design. This was one of the first applications of computers in hydrological simulation. I went on to work on the hydrological design of a number of the last reservoir schemes to be built in
England and Wales. I was looking into new potential reservoirs at North West Water when I realised I needed to broaden my work experience and moved into operations. I worked as
technical manager for distribution – covering all aspects of water distribution – mains refurbishment, procurement of pipes and fittings, leakage, digital mapping, water quality, levels
of service etc. etc. I was involved in the development of what are called asset management plans which were introduced following privatisation and have to be completed every 5 years. It was
when I was doing the one for 1994 that I found that Allan Lambert was involved with the national leakage initiative and we re-established our working relationship. It was then when I
worked out how much leakage we had in North West Water and how much we should be able to save and avoid a new reservoir. Water losses – that hidden resource!!
In 1994 I was given a job which was purely leakage – to drive out these reductions – as we say in England – “put your money where your mouth is”!! It did not work to start with and I was in
great danger!! But fortunately someone was looking after me and delivered the worst drought that the North West of England had very experienced! This started in June 1995 and lasted for
about 18 months. The only chance of maintaining water supplies to 7 million people was to make significant reductions in leakage. And the business had to provide me with the necessary resources!
In the end, leakage management became very political at national level (and ended up with a change in government). As a result the industry was forced into mandatory leakage targets. By 2000 we had reduced leakage from 950Ml/d to 450Ml/d. It was a baptism of fire but great times.
I had to learn very quickly and I have to say that I relied heavily on Allan Lambert particularly to start with. I immersed myself into the national committees in the UK and worked on many of the
research projects.

3. What mentors did you have and what useful tips have you received? What books do you recommend?

As I mentioned earlier Allan Lambert has been a great mentor all through my career be that on hydrology, reservoir control curves and now leakage. When I was considering leaving UU in 2002 I went to see Allan and said what I was contemplating. He said – “no problem”, “there is plenty of work out there in the world, sign up here for the IWA Water Loss Task Force and I will introduce you to the group”. So within 3 months I was at the IWA Water Loss conference in Cyprus! There I found old friends – Tim Waldron (who had worked with me at UU) and Stuart Hamilton (who I had employed at UU – his first job after setting up on his own) and lots of new friends and colleagues. I think my main mentors have been Allan (of course), Tim Waldron, Alex Rizzo, Stuart Hamilton and a close colleague, Stuart Trow. And they still remain mentors
today. Hopefully they view it as a two way street!

In terms of books – I don’t think you can go wrong in using something like “Water Supply”, mentioned above, to give you a good grounding in the general operation of a water supply network – it can be all too easy to immerse yourself in the detail of water losses without seeing the big picture of the whole hydrological cycle and the operation of a water network. When it comes to water losses, then I would recommend the IWA books “Losses in Water Distribution Networks” by Trow and Farley and “Water Loss Control” by Julian Thornton. But I would also ecommend the WRc “Managing Leakage” manuals as excellent basic grounding in the detail of understanding leakage. And I am always referring to Allan Lambert’s Aqua Paper on “A Review of Performance Indicators for Real Losses from Water Supply Systems” – compulsory reading
for you all!!

4. Could you tell us something about some of the most interesting projects that you participated in? What conditions did you encounter?

I could (and often do) talk endlessly about my many experiencing when in charge of the water loss reduction programme at UU. At the start I had to try and convince the operational teams in the districts what the level of leakage was and how much we were going to save!

I would get the responses: “No we can’t have that much leakage!”, “You would have to walk round in wellington boots if there was that much leakage!”, ”It is all due to the water supply input meters reading high”, “People use a lot more water than we think” (household use was not metered at that time) , “Night flows are the lowest they have ever been” etc. etc.!!!

Then there was the time that I had to issue an edict that from that particular day on we only did pressure management not pressure reduction and we only fitted PMVs and not PRVs!! This was after a discussion with the managing director after the company had received bad publicity from the Fire Brigades.

At the height of the drought the TV station covering the North West of England ran an item called “Leak of the Week” every Friday teatime. This was compulsory watching and I had to make sure we had found and sorted it before the following Friday. Because of our work during the drought we ended up finding duck ponds that were being fed by leaks, marshy areas on our sewage works fed by leaks etc. etc.. One of the more interesting projects was trying to get to
grips with reconciling Top Down and Bottom Up leakage on the integrated zone which amounted to 170Ml/d. That unearthed some very “interesting” anomalies!!

Since leaving UU I have worked on a number of interesting projects be that for clients in various parts of the world, research projects in the UK or developing my own Leakage Game (Water Detectives No 7 August 2014). But in many respects some of the more interesting work has been in conjunction with colleagues on the IWA Water Loss Task Force where I have worked on things such as the apparent loss group and the pressure group that lead to the pressure – burst
frequency work that we are covering during the conference.

5. Have you ever been in Romania? If yes, on what occasion?

No, I have not been to Romania. I had intended to come to the IWA Water Loss conference in Bucharest in 2007. I was all booked in, flights paid and a paper written and accepted. But two days before the conference my wife had an horrific accident and had to give back word in order to stay with her. Stuart Trow, a colleague of mine presented my paper for me. So I am looking forward to making amends.

6. Are you familiar with the Balkan problems related to water loss? What do you think is the key difference between those with high losses (Romania, Serbia, Bulgaria) and those with low losses
(Germany, Netherlands)?

I am familiar with the problem (I think!!). I was fortunate that my very first job when I left United Utilities was to as special leakage advisor to the concessionaire at Sofiska Voda. When I started reviewing the figures I could not believe the burst frequency. I went back and said there must be a mistake. But no – the figures were correct. I understand this was due to the use of very poor materials for pipes and fittings following the war. Am I right? Could be a good area for discussion – hopefully over a few beers!
I have some experience of investigating the low levels of leakage in the Netherlands being one of a small group of leakage practitioners that visited the Netherlands in order to try and understand
their performance. Very enlightening! I have my own theory on some elements that contribute to this, one of which is in direct contrast to the one I found in Sofiska Voda.

7. In the past, leakages were discovered by direct listening to the pipes, and now there are technologies that can “discover” these leakages using the drones and the satellites. What do you think is the direction for the future? Will we be able to accurately locate leakages solely using computer software?

Ah! That is a great question! We (UU) looked into overflying our aqueducts during the 1995/96 drought with some (but limited) success. We eventually identified the best spectrums to be using
but it was very expensive at the time and so was not taken up into mainstream leakage detection, so it is interesting to see that the cost of doing it may well be coming down with the use of drones and satellites and may make this technology economic. But to me (though I stand to be corrected!) it would only be appropriate for supply lines under open vegetation. However I am a great believer that one day one should be able to identify and locate leaks solely by computer software. This will need the network to be significantly wired up with smart meters on properties but primarily with correlating noise loggers on every fitting in the network and very significant data processing systems (such as TaKaDu) back at base. I wrote my key note paper to the IWA Water Loss conference in Vienna in 2014 on this very topic (happy to forward a copy if you
want). If we are happy to define “accurately” as +/- 2m say then I think I agree with you, but I would always send a leak detection specialist out to top sound and confirm that it is a leak and to
confirm the exact location!
But I would always countenance against diving straight into very sophisticated and probably very expensive and possibly inappropriate technology before understanding and sorting out the
basics first. You run the risk of “not see the wood for the trees”!

8. What do you think about Water Loss Detectives magazine?  What advice can you give us?

I think it is great. I have a lot of respect for anyone who can keep such a concept running. I attempted to do something similar during the drought at UU in order to try and keep everyone
informed and involved. But I failed miserably! The effort involved is considerable (and not one of my strengths!). It is so easy to produce No 1 and possibly No2 – then the ideas start drying up and the effort needed chasing people to write articles gets harder and harder. So congratulations!
You have done well in getting a very wide breadth of topics and contributors and to keep teh concept going.
In terms of giving you advice! Well I am not sure that anything I can say would help – but perhaps one idea may be to ask people who have done papers to the main IWA Water Loss conferences either to repeat their paper here – or better still encourage them to modify/update them and give them a forum for that!

Thank you
See you in Bucharest.
I look forward to that!